As the flawlessly smooth walls drifted by him, unbroken by any markings, unscarred by age, Kimball could not help recalling Alice's fall down the rabbit hole. It was an uncomfortable memory, for that strange descent had led to an underworld where magic reigned, and the normal laws of nature were overthrown. For the first time, he began to wonder if this might be happening here.
From the very beginning, they had known that they were dealing with a science greater than man's. But they had not doubted-they dared not doubt-that it was a science that they could ultimately understand. As the light below grew in size and brilliance, Kimball felt the first, appalling intimations that this might not be true.
It was a thought to hold at arm's length, especially in surroundings such as these. He was coming to the end of the line, and was already far below the last reflected rays of the sun. It required an act of physical courage to put the binoculars to his eyes, and to stare steadfastly at the tunnel's glowing end.
Bowman was right. He could have been looking at the Milky Way. The field of the instrument was full of stars- thousands of them, shining in the black core of this tiny, frozen world.
Some facts are so incredible that they are believed at once, for no one could possibly have imagined them. Kimball never doubted the message of his eyes, and did not try to understand it. For the moment, he would merely record what he saw.
Almost at once, he noticed that the stars were moving. They were drifting out of the field on the left, while new ones appeared from the right. It was as if he was looking down a shaft drilled clear through Jupiter V, and observing the effects of its rotation as it turned on its axis every ten hours.
But this, of course, was impossible. They had mapped and surveyed the entire area of the satellite, deliberately searching for any other entrance, and had found nothing but unbroken rock and ammonia ice. Kimball was quite certain that there was no window at the antipodes through which stars could shine.
And then, rather belatedly-he was, after all, a communications engineer and not an astronomer-he noticed something that totally demolished this theory. Those stars were drifting to his left; if the movement had been due to Jupiter V's spin, it should have been in a direction almost at right angles. So the rotation of the little moon had nothing whatsoever to do with it....
That was quite enough for one man, on one visit.
"I'm coming up," he called Bowman. "We'd better talk this over with Vic-maybe he has an explanation."
When he had rejoined Bowman on the surface of the satellite, it seemed to him that the once incredible sight of Jupiter spanning the sky was as familiar and reassuring as a quiet country landscape back on Earth. Jupiter they understood-or where it still held mysteries, they were not such that sapped the mind. But the thing beneath their feet defied all reason and all logic.
They waited, lost in their own thoughts and saying nothing, merely listening for the first sound of Discovery's beacon as she came up over the horizon. Luckily for their peace of mind, she was exactly on time; still without a word, they jetted themselves up toward her and, ten minutes later, were jockeying themselves through the airlock.
Astronauts are somewhat addicted to harmless practical jokes; it is one of their ways of asserting superiority over the Universe, which has no sense of humor. Kaminski and Hunter might, for a moment, have thought that the others were pulling their legs, but their doubts lasted no more than seconds.
Two orbits later, they went down themselves, taking cameras with long-focus lenses to record the star-patterns at the bottom of the shaft. Within minutes, Kaminski had an additional piece of information. He timed the movement of the stars across the opening, and calculated that it took fifteen hours for a complete revolution-as against Jupiter V's ten. It seemed that, by some magic of space or time, they were looking out into a strange universe through a window in the surface of a world that turned upon its axis once in every fifteen hours.
Kaminski was almost half a mile down the shaft when with shocking abruptness, the window looked upon a different scene.
SOMETHING IS SERIOUSLY WRONG WITH SPACE
Hunter, up on the surface, heard and recorded every word.
"I'll try a long exposure with the thousand-millimeter lens," Kaminski began. "I hate to confess it, but this is the first time I've ever done any astronomical photography. ... Hello!"
"What's happening?"
"The end of the slot's getting lighter. Yes, there's no doubt of it. There's a very faint glow along one side. You know, it looks like-my God-that's what it is!!"
"What, for heaven's sake?!"
"Sunrise! Sunrise! Leave me alone-I want to watch."
There were maddening minutes of silence, during which Hunter could hear only Kaminski's heavy breathing and, occasionally, the sound of instruments and controls being operated. Then, at long last, the astronomer spoke again, his voice full of wonder.
"It's a sun, all right. And it's enormous-it's completely filling the view. If I could see it all at once, it would look as big as Jupiter.
"And it's not a G-zero type like our sun. It's very dull and red-I don't even need dark filters on the telescope. Must be a red giant, like Antares. That's an idea-maybe it is Antares. Ah, here comes a sunspot-looks pretty small, but it could be as big as our whole sun...."
His voice trailed off into silence and again Hunter possessed himself in patience until at last Kaminski said: "Still no change-that sun's still blocking the view. It'll take hours to move out of the way. Let's get back to the ship-I want to study these photos. And I'd like to try an experiment, if I can talk Dave into it."
"What sort of experiment?"
"We still have most of our instrumented probes. This is the place to use them."
When they returned to the ship, Bowman was at first reluctant. If anything was dropped down the shaft, he pointed out, even this low gravity could give it a terminal speed of over a hundred miles an hour. There was no telling what damage it might do-or what reactions it might produce.
Kaminski finally settled the argument by pointing out that the designers of this place would certainly have protected their handiwork against such trivial accidents. Every few centuries, a large meteor must plunge into the chasm at a far higher speed than any falling probe could attain.
Once the project had been agreed upon, Kimball acted as bombardier. Since the orbiting Discovery could track the probe only during the few seconds while it was passing directly over the slot, space capsule Alice was fitted with receiving gear. Kimball dropped the probe at the exact center of the chasm, then flew to the edge and waited on the brink, Alice's receiving antenna jutting out over the abyss.
At first the probe fell with the lethargic slowness to be expected in Jupiter V's gravity field. Its instruments recorded a very slight temperature rise, but nothing else of importance. There was no radioactivity, no magnetic field.
And then, five miles down, it began to accelerate. Its signals started to drop rapidly in pitch, indicating a Doppler effect of astonishing magnitude. Kimball had to continually retune the receiver in order to keep track of the signals, and the radar started to indicate impossible ranges and velocities. In a few seconds, the probe was two hundred miles away-which, taken at face value, meant that it had gone right through Jupiter V and out the other side. Thereafter, it became more and more difficult to detect, and swiftly passed beyond the tuning range of the receiver. On the last contact, it had descended nine thousand and fifty miles down a hole which under no circumstances could be more than a hundred miles deep-the diameter of the tiny moon.
The radar was working perfectly; Kimball checked it with the utmost care as soon as he got back to the ship. The trouble must lie in Jupiter V-and Hunter neatly summed up what everybody was now beginning to suspect.
"I'm afraid," he said, "that there's something seriously wrong with space."
"A long time ago," said Kaminski, "I came across a remark that I've never forgotten-though I can't remember who made it. 'Any sufficiently advanced
technology is indistinguishable from magic.' that's what we're up against here. Our lasers and mesotrons and nuclear reactors and neutrino telescopes would have seemed pure magic to the best scientists of the nineteenth century. But they could have understood how they worked-more or less- if we were around to explain the theory to them."
"I'd be glad to settle without the theory," remarked Kimball, "if I could even understand what this thing is-or what it's supposed to do."
"It seems to me," said Bowman, "that there are two possibilities-both just about equally impossible. The first is that Jupiter V is hollow-and there's some kind of micro-universe down there. A whole galaxy a hundred miles across."
"But the probes went thousands of miles, according to the radar readings."
"There could be some kind of distortion. Suppose the probes got smaller and smaller as they went in. Then they might seem to be thousands of miles away, when they were still really quite close."
"And that," said Kaminski, "reminds me of another quotation-one of Niels Bohr's. 'Your theory is crazy- but not crazy enough to be true.' "
"You have a crazier one?" asked Hunter.
"Yes, I do. I think the stars-and that sun down there- are part of our own universe, but we're seeing them through some new direction of space."
"I suppose you mean the fourth dimension."
"I doubt if it's anything as simple as that. But it probably does involve higher dimensions of some kind. Perhaps non-Euclidean ones."
"I get the idea. If you went down that hole, you'd come out hundreds or thousands of light- years away. But how long would the journey really be?"
"How long is the journey from New York to Washington? Two hundred miles if you fly south. But twenty-four thousand if you go in the other direction, over the North Pole. Both directions are equally real."
"I seem to remember," said Bowman, "that back on Earth you once told me that shortcuts through space-time were scientific nonsense-pure fantasy."
"Did I?" replied Kaminski, unabashed. "Well, I've changed my mind. Though I reserve the right to change it back again, if a better theory comes along."
"I'm a simpleminded engineer," said Hunter rather aggressively. "I see a hole going into Jupiter V, and not coming out anywhere. But you tell me that it does come out. How?'
Everyone waited hopefully for Kaminski to answer. For a moment he hemmed and hawed, then he suddenly brightened.
"I can only explain by means of analogy. Suppose you were a Flatlander, an inhabitant of a two- dimensional world like a sheet of paper-unable to move above or below it. If I drew a circle in your flat world, but left a small gap in it, you would say that the gap was the only way into the circle. Right?"
"Right."
"If anyone went into the circle, they could only come out the same way?"
"So that's what you're driving at. The circle could be a cross-section of a tube passing through Flatland. If I was clever enough to crawl up the tube, by moving into the third dimension, I would leave my flat universe altogether."
"exactly. But the tube might bend back into Flatland again, and you could come out somewhere else. To your friends, it would seem that you'd traveled from A to B without crossing the space between. You'd have disappeared down one hole and emerged from a totally different one, maybe thousands of miles away."
"But what advantage would that be? Surely the straight line in Flatland itself would still be the shortest distance between A and B."
"Not necessarily. It depends what you mean by a straight line. Flatland might really be wrinkled, though the Flatlanders wouldn't be able to detect it. I'm not a topologist, but I can see how there might be lines that were straighter than straight, if some of them went through other dimensions."
"We can argue this until kingdom come," said Hunter. "But supposing it's true-what shall we do about it?"
"There's not much we can do. Even if we had an unlimited fuel and oxygen supply, it might be suicide to go into that thing. Though it may be a shortcut, it could be a damn long one. Suppose it comes out somewhere a thousand light-years away-that won't help us, if the trip takes a century. We wouldn't appreciate saving nine hundred years."
That was perfectly true; and there might be other dangers, as inconceivable to the mind of man as this anomaly in space itself. Discovery had come to the end of her travels; she must remain here in an eternal orbit, just a few miles from a mystery that she could never approach.
Like Moses looking into the promised land, they must stare at marvels beyond their reach.
BALL GAME
After a while they began to call it the Star Gate; no one was quite sure who coined the name. And because the human mind can accept anything, however strange, its mystery soon ceased to haunt them. One day, perhaps, they would understand how the stars were shining down there at the bottom of that chasm; the night sky, reflected in a pool of still water, might have seemed just as great a mystery to early man.
They still had twenty days of operating time before they would have to go into hibernation, and there was enough fuel for the pods to make five more trips down to the surface. Bowman allowed three visits, at internals of a week, and then left the pods in their airlocks, fully provisioned, ready for any future emergency that might arise.
The descents taught them little more than they already knew. They watched the regular transit of those strange stars and the giant red sun, drifting with clockwork precision across the distant end of the Star Gate-still in a direction, and at a speed, that had nothing to do with the spin of Jupiter V itself.
Kaminski brooded for hours over his photographs, trying to identify the star patterns with the aid of the maps stored in Athena's memory. His total failure neither disappointed nor surprised him. If indeed he was looking out through a window onto some remote part of the Galaxy, there was no hope of recognizing the view. One of those faint stars might even be the Sun; he could never identify it. From a few score light-years away, Type G-zeroes are as indistinguishable as peas in a pod.
The three remaining instrumented probes were dropped at intervals of a week-the last one, just before hibernation was due to commence. Each performed in an identical manner, dwindling away into impossible distances before its signals were lost. The record depth-in this hundred mile-diameter world!-was eleven thousand miles....
After that, they had done everything that was humanly possible, their stores were almost exhausted, and it was time to sleep. In one sense, their mission had been a success, they had discovered what they had been sent to find-even if they did not know what it was. But in another, the expedition had failed, since they could not report their findings to Earth. All Kimball's attempts to re-establish communications with jury-rigged antennas and overloaded output circuits had been successful. The daily messages and news reports continued to come in, and were at once encouraging and frustrating. It was good for their morale to know that Earth, and their friends, had not forgotten them, and that the preparations for their return were going ahead at the highest priority. But it was maddening not to be able to reply, and to be the custodians of a secret that would rock human society to its foundations.
And it was also unsettling to hear the messages that continued to arrive for Poole and Whitehead, and to see the faces of their friends and relatives as they sent greetings to men who had been dead for months. It was a constant reminder of their own uncertain future, now that it was time for their hibernation to begin.
There were better places to have slept, but they had little choice in the matter. They could only hope that Jupiter V would continue to treat them with complete indifference, as they circled it every ninety minutes until, three or four or five years from now, the recovery expedition arrived.
During the last days they checked every detail of the ship, closed down all unnecessary equipment, and tried to anticipate everything that could possibly go wrong. The shadow of Poole's death often lay heavy on their minds, but they never mentioned it. Whether it had been due to a random failure, or a loss o
f tolerance, there was nothing that could be done. They had no alternative but to proceed as planned.
One by one, their work completed, they made their goodbyes and went to rest, until at last only the captain was left. To Bowman, all this had a haunting familiarity; once before he had cracked the same jokes, made the same-he hoped-temporary farewells, and had been left alone in the sleeping ship.
He would wait two days before he followed the others. One would be long enough to check that everything was running smoothly; the second would be his own-to share with the last game of the World Series.
Curiously enough, while on Earth, he had never been an avid baseball fan, but like all the members of the crew he had acquired a passionate interest in the sport programs relaying from Earth. One day more or less made no difference to Bowman now, and he was anxious to see if the New York Yankees would make a comeback after their long years in the doldrums. He doubted it; the Mets seemed more impregnable than ever.